Electrical socket having a movable cover



Feb. 1, 1955 T. A. DAVIDSSON 2,701,347

ELECTRICAL SOCKET HAVING A MOVABLE COVER Filed Oct. 21, 1953 IN VEN TOR.

ATTORNEYS United States Patent ELECTRICAL SOCKET HAVING A MOVABLE COVERTage Arnold Davidsson, Gothenburg, Sweden Application October 21, 1953,Serial No. 387,453

Claims priority, application Sweden December 23, 1952 3 Claims. (Cl.339-40) The present invention relates to electrical pin-andsocketcouplings of the kind provided with a cover plate situated in front of apair of socket tubes adapted to receive the pins of a plug and providedwith openings registering with the socket tubes, and in which there isprovided a movable spring-actuated shutter mechanism behind the coverplate and adapted to uncover the socket tubes by being simultaneouslyactuated on the insertion of the two plug pins.

The object of devices of this character is to prevent children andothers from making contact with live parts of the coupling.

Devices of this kind already known, in which the openings in the frontplate have the form of circular holes conforming with the plug pins,suffer from the disadvantage that they must of necessity becomparatively thick owing to the fact that an axial movement of the plugpins is required for operating the shutter mechanism.

The object of the present invention is to overcome this disadvantage,and said invention is broadly characterised in that the openings in thecover plate consist of elongated parallel slots each having one end inregister with one of the socket tubes, the shutter mechanism being sodisposed in relation to the slots, that it is brought to a positionuncovering the socket tubes by moving the plug pins along the slots in adirection towards the ends thereof which are disposed over the sockettubes.

In such a device the socket coupling can be constructed with acomparatively small dimension in a direction perpendicular to the planeof the cover plate, and in addition the further advantage is obtained,viz: that it is easy to find the socket tubes with the plug pins byusing the slots as guides.

In the accompanying drawing there is shown an embodiment of theinvention, and in said drawing:

Figure 1 shows a front view of a socket coupling according to theinvention with the shutter mechanism in the safety position;

Figure 2 shows the shutter mechanism as seen from the back, also in thesafety position;

Figure 3 is a view mainly corresponding to Figure 2 but with the shuttermechanism in a position uncovering the socket tubes;

Figure 4 is a cross section through the device along the line IV--IV inFigure 2, and

Figure 5 is a perspective view of a detail of the shutter mechanism.

The base plate carrying the socket tubes is not shown in the drawing andcan be of any suitable design.

In the drawing 1 denotes a cover plate securable to a base plate bymeans of screws 2 and provided on its front face with a circular recess3, the bottom of which is pierced with two elongated, parallel slots 4and 5, each having one end in register with one of the socket tubes 6,6a (indicated by dotted lines in Figure 4). In a roughly U-shaped recessin the back of the cover plate there are housed two similar shutters 7and 7a respectively, which are slidable in a direction perpendicular tothe axis of the slots 4, 5. As shown in Figure 5 the shutters consist ofthin U-shaped plates with parallel shanks 9, l0 and 9a, 10a respectivelyof unequal length, of which the longer 9 (9a) is obliquely cut off atits free 2,701,347 Patented Feb. 1, 1955 Ice end so as to form aslopping edge 11 and 11a respectively. The bases and short shanks of theshutters overlap each other and are guided by opposite walls 12 and 12::respectively, of the recess A. Each shutter is pressed by a spring 13and 13a respectively, which normally hold the shutters in the positionshown in Figures 1 and 2 in which position the shank 9 of the shutter 7covers the socket tube 6 and the shank 10 of the same shutter covers thesocket tube 6a, while the shanks 9a and 10a of the shutter 7a in asimilar way also cover the socket tubes. In this covering or safetyposition of the shutters the sloping edges 11, 11a of the longer shanks9, 9a cross the two slots 4, 5 obliquely at a distance from the endssituated on the periphery of the recess 3, so that by inserting the plugpins (indicated by dotted lines 14 in Figure 3) in said ends of theslots 4, 5 and sliding the same along the slots to their opposite endsthe shutters 7, 7a will be moved against the action of the springs 13,13a to the position shown in Figure 3. By this displacement of theshutters 7, 7a their shanks uncover the socket tubes 6, 6a, so that theplug pins 14 can be pushed home in the socket tubes 6, 6a. Behind thecover plate 1 there is secured a bottom plate 15, which is partly brokenaway in Figure 2 and entirely removed in Figure 3, and which is providedwith holes 16 registering with the socket tubes 6, 6a.

The invention is not limited to the embodiment described above and shownin the drawing but may be varied in detail without departing from thespirit of it. For instance, the shutters may be pivotally mountedinstead of slidable.

What I claim is:

1. An improvement in cover plates for electrical plug and socketcouplings wherein said socket has tubes for receiving pins of said plugcomprising a cover plate having elongated substantially parallel slotspositioned for having one end thereof registering with the tubes of saidsocket, when said cover plate is mounted thereon, a pair of plates eachslidably mounted on said cover plate for movement substantially parallelto said cover plate laterally of said slots, each of said plates havinga shoulder extending from an end thereof, resilient means tending toposition said plates covering the tube registering portion of said slotswith each shoulder extending diagonally of one of said slots for beingengaged by said plug pins when moving longitudinally of said slotswhereby said plates are moved from their tube covering position.

2. An improvement in cover plates for electrical plug and socketcouplings wherein said socket has tubes for receiving the pins of saidplug comprising a cover plate having elongated substantialy parallelslots each for being in register at one end with one of said tubes whensaid cover plate is mounted over said socket, a pair of fiatsubstantially U-shaped plates slidably mounted on said cover plate withone leg extending longitudinally of one of said slots covering the tuberegistering portion thereof and having the end of said leg thereofextending diagonally of its corresponding slot, resilient means tendingto retain said plate legs in their slot covering position whereby saiddiagonal end can be contacted by said plug pins when movinglongitudinally of said slots displacing said plates laterally andopening said slots.

3. An improvement in cover plates as claimed in claim 1, wherein saidcover plate has recesses provided therein for guiding said plates to andfrom their slot covering positions.

References Cited in the file of this patent UNITED STATES PATENTS1,736,269 Lawrence Nov. 19, 1929 FOREIGN PATENTS 508,415 Great BritainJune 30, 1929

